Case-hardening or cementing material.



.State of Pennsylvania, have made a new and ash, caustic soda or barium carbonate, has

HUGH RODMAN, OF PIT 'DSBUR-G, PENNSYLVANIA.

CASE-HARDENING OR CEMENTING lllIA'lIERIAL Specification of Letters Patent.

Patented Feb. 15, 1910.

No Drawing. Original application filed May 21, 1909, Serial No. 497,555. Divided and this application filed October 8, 1909.

To all whom 'it may concern:

Be it known that I, HUGH RoDMAN, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and useful Invention in Case-Hardening or Cementing Material, of which the following is a specification.

This invention relates to case-hardening or cementing material and this application is a division of an application for Letters Patent filed by me on May 21, 1909, and given Serial Number $7,555.

I have found, as described by me in a copending application for Letters Patent, Serial No. 496,271, filed on or about May 15, 1909, that the ordinary coke of commerce when pulverized or granulated and intimately mixed with proper proportions of an energizing substance, such as lime and sodathe property given to it of rendering it active as a case-hardening or cementing material. By energizing substance, I mean such material, not necessarily carbonaceous material, as will when added to an inactive carbonaceous substance, render such carbonaceous substance active, as a carbonizing agent. It is dillicult, however, in the case of insoluble substances to get and maintain the intimate mixture necessary, and in the case of soluble.substances it is difficult to get enough of the substance into the pores of the coke.

I have found that I am able to obtain intimate mixtures of coke and energizingsubstances, such as lime, soda-ash, caustic soda or barium carbonate, or mixtures thereof. by mixing the proper proportions of energizing substance with coking coal, preferably finely powdered, and then heating the mixture at a temperature sufficientv to coke the coal. The result is an impregnated coke which may be crushed and screened to the size desired for commercial case-hardening or cementing material. In appearance the resulting product closely resembles non-impregnated coke, but, however, it is a little softer and will absorb moisture more rap idly.

I have found that, if desired, case-hardening or cementing may be carried on during the process of coking the mixture of coal and energizer and the resulting product may later be crushed and screened for use as a commercial case-hardening or cementing Serial No. 521,778.

material and apparently has all of the properties it would have had if the case-hardening or cementing had not been carried on during the coking operation.

I have found in practice that excellent case-hardening or cementing material may be produced by mixing ten parts by Weight of powdered lime and five parts of powdered soda-ash Withonehundred parts of slack coking coal and then subjecting the mixture to a temperature of about 1500 Fahrenheit until the coal is thoroughly coked. I have also found that an intimate mixture of lime. and coke may beobtained by. coking the iiiixture, of slack coking coal and limestone. \Vhen this is done the limestone obviously is changed to lime, and the resulting product is coke impregnated with lime.

In actual practice, I have found that if the coked product be exposed to the atmosphere, the lime therein is liable to become air slaked, but it will nevertheless have energizing properties not present in the lime stone before the coking takes place. Limestone, prior to being calcined, is not useful as an energizing substance because of its surface-attacking properties. I have also found that other coking materials than bi tuminous coal may be used and I have obtained excellent results from crude oil and the heavy hydro-carbons resulting from the distillation of crude oil.

Having thus described my invention, what I claim is: i

l. The method of producing cementing or casehardening material which consists in coking a mixture of coking substance and material capable of being transformed into an energizing substance during the coking process.

2. The method of producing cementing or case-hardening material which consists in coking a mixture of coking coal and material capable of being transformed into an energizing substance during the coking process.

3. Cementing or case hardening material containing a coked mixture of carbonaceous material and limestone.

In testimony whereof, I have hereunto subscribed my name this 27 day of September, 1909.

HUGH RODMAN.

Witnesses C. W. MoG-nnn, C. W. BALLAY. 

